The present invention is a multi-purpose, computer controlled, machine tool for performing secondary operations on lathe turned metal parts. The machine tool of the present invention is designed for versitility and adaptability. Various combinations of machining heads and alternative configurations may be utilized to lower cost and increase efficiency for high volume machining operations.
Machining holes, commonly called crossholes, through the wall of material between the outside diameter (O.D.) and inside diameter (I.D.) of a workpiece, perpendicular to the workpiece centerline, is a common machining operation. Crossholes are typically machined by one of three methods:
In the first method, suitable for relatively low volume production, the lathe or turning machine tool has the capability to stop, and perhaps index, a spindle holding the workpiece. The crosshole is machined using a special live tooling spindle which supports a cutter for machining the crosshole. Generally there is no provision for a guide bushing to support the cutter in the live tooling spindle. Most turning machine tools are not equipped to lock or index the main spindle.
A second method for machining crossholes requires that the turned workpieces be machined in a second machine tool such as a drill press or vertical milling machine. The workpiece is generally located with it""s centerline horizontal in a fixture capable of indexing. A guide bushing may or may not be used and, depending on the capacity and capability of the machine tool, multiple fixtures and computer control may be used. This method usually does not lend itself well to automated loading and unloading of the workpiece and typically workpiece features are machined individually on one workpiece at a time. Safety concerns and the relative inefficiencies associated with manual loading make this method suitable only for low to medium volume production.
A third method of machining crossholes involves the use of a special purpose machine tool custom designed and built for a particular application. Typically a special purpose machine tool is dedicated to a single workpiece contiguration; at most it might accommodate a limited family of parts. Using a special purpose machine tool, automatic workpiece loading and unloading capabilities may be incorporated, making this method suitable for high volume. production.
The principal drawback of a special purpose machine tool is that it is labor intensive and expensive to change to a different workpiece configuration. When the geometry of the workpiece changes or the workpiece becomes obsolete the custom built machine tool usually requires extensive redesign and reconfiguration or may itself become obsolete. Moreover, for machining workpieces with complex geometries, it may be impossible or impractical to create a single special purpose. machine tool. Several custom machine tools may be required, resulting in inefficiencies, inaccuracies, and additional costs associated with multiple part handlings and set-ups.
It is an object of the present invention to provide a single multi-purpose machine tool that provides the ability to machine many workpiece feature geometries at high volume production efficiencies.
It is another object of the present invention to provide a multi-purpose machine tool with the capability for set-up changes to be made quickly and easily by having a vertical machining head and indexer with integral workholder mounted on a slide assemblies.
It is yet another object of the present invention to provide a multi-purpose machine tool that has the capability to make dimensional adjustments by computer control.
It is yet another object of the present invention to provide a multi-purpose machine tool for which a combination of crosshole features, such as holes, slots and windows may be configured in a single set-up.
It is yet another object of the present invention to provide a multi-purpose machine tool capable of combining crosshole and end working features in a single set-up.
It is yet another object of the present invention to provide a multi-purpose machine tool in which various combinations of machining heads may or may not operate simultaneously.
It is yet another object of the present invention to provide a multi-purpose machine tool having a built-in workpiece loading and unloading capability with predictable cycle time and reliability.
It is a further object of the present invention to provide a multi-purpose machine tool having multiple axis motion capability.
According to the present invention, a multi-purpose machine tool having multiple horizontal machining heads and at least one vertical machining head slidably mounted on a gantry spanning the workpiece, and an indexer with integral workholder capable of two degrees of freedom is provided for performing high volume machining operations.